package birdwatcher

import (
	"github.com/alice-lg/alice-lg/backend/api"

	"log"
	"sort"
)

type Birdwatcher struct {
	config Config
	client *Client
}

func NewBirdwatcher(config Config) *Birdwatcher {
	client := NewClient(config.Api)

	birdwatcher := &Birdwatcher{
		config: config,
		client: client,
	}
	return birdwatcher
}

func (self *Birdwatcher) Status() (api.StatusResponse, error) {
	bird, err := self.client.GetJson("/status")
	if err != nil {
		return api.StatusResponse{}, err
	}

	apiStatus, err := parseApiStatus(bird, self.config)
	if err != nil {
		return api.StatusResponse{}, err
	}

	birdStatus, err := parseBirdwatcherStatus(bird, self.config)
	if err != nil {
		return api.StatusResponse{}, err
	}

	response := api.StatusResponse{
		Api:    apiStatus,
		Status: birdStatus,
	}

	return response, nil
}

// Get bird BGP protocols
func (self *Birdwatcher) Neighbours() (api.NeighboursResponse, error) {
	bird, err := self.client.GetJson("/protocols/bgp")
	if err != nil {
		return api.NeighboursResponse{}, err
	}

	apiStatus, err := parseApiStatus(bird, self.config)
	if err != nil {
		return api.NeighboursResponse{}, err
	}

	neighbours, err := parseNeighbours(bird, self.config)
	if err != nil {
		return api.NeighboursResponse{}, err
	}

	return api.NeighboursResponse{
		Api:        apiStatus,
		Neighbours: neighbours,
	}, nil
}

// Get filtered and exported routes
func (self *Birdwatcher) Routes(neighbourId string) (api.RoutesResponse, error) {
	// Exported
	bird, err := self.client.GetJson("/routes/protocol/" + neighbourId)
	if err != nil {
		return api.RoutesResponse{}, err
	}

	// Use api status from first request
	apiStatus, err := parseApiStatus(bird, self.config)
	if err != nil {
		return api.RoutesResponse{}, err
	}

	imported, err := parseRoutes(bird, self.config)
	if err != nil {
		return api.RoutesResponse{}, err
	}

	gateway := ""
	if len(imported) > 0 { // infer next_hop ip address from imported[0]
		gateway = imported[0].Gateway //TODO: change mechanism to infor gateway when state becomes available elsewhere.
	}

	// Optional: Filtered
	bird, _ = self.client.GetJson("/routes/filtered/" + neighbourId)
	filtered, err := parseRoutes(bird, self.config)
	if err != nil {
		log.Println("WARNING Could not retrieve filtered routes:", err)
		log.Println("Is the 'routes_filtered' module active in birdwatcher?")
	} else { // we got a filtered routes response => perform routes deduplication
		result_filtered := make(api.Routes, 0, len(filtered))
		result_imported := make(api.Routes, 0, len(imported))

		importedMap := make(map[string]api.Route) // for O(1) access
		for _, route := range imported {
			importedMap[route.Id] = route
		}
		// choose routes with next_hop == gateway of this neighbour
		for _, route := range filtered {
			if route.Gateway == gateway {
				result_filtered = append(result_filtered, route)
				delete(importedMap, route.Id) // remove routes that are filtered on pipe
			} else if len(imported) == 0 { // in case there are just filtered routes
				result_filtered = append(result_filtered, route)
			}
		}
		sort.Sort(result_filtered)
		filtered = result_filtered
		// map to slice
		for _, route := range importedMap {
			result_imported = append(result_imported, route)
		}
		sort.Sort(result_imported)
		imported = result_imported
	}

	// Optional: NoExport
	bird, _ = self.client.GetJson("/routes/noexport/" + neighbourId)
	noexport, err := parseRoutes(bird, self.config)
	if err != nil {
		log.Println("WARNING Could not retrieve routes not exported:", err)
		log.Println("Is the 'routes_noexport' module active in birdwatcher?")
	} else {
		result_noexport := make([]api.Route, 0, len(noexport))
		// choose routes with next_hop == gateway of this neighbour
		for _, route := range noexport {
			if route.Gateway == gateway {
				result_noexport = append(result_noexport, route)
			} else if len(imported) == 0 { // in case there are just filtered routes
				result_noexport = append(result_noexport, route)
			}
		}
	}

	return api.RoutesResponse{
		Api:         apiStatus,
		Imported:    imported,
		Filtered:    filtered,
		NotExported: noexport,
	}, nil
}

// Make routes lookup
func (self *Birdwatcher) LookupPrefix(prefix string) (api.RoutesLookupResponse, error) {
	// Get RS info
	rs := api.Routeserver{
		Id:   self.config.Id,
		Name: self.config.Name,
	}

	// Query prefix on RS
	bird, err := self.client.GetJson("/routes/prefix?prefix=" + prefix)
	if err != nil {
		return api.RoutesLookupResponse{}, err
	}

	// Parse API status
	apiStatus, err := parseApiStatus(bird, self.config)
	if err != nil {
		return api.RoutesLookupResponse{}, err
	}

	// Parse routes
	routes, err := parseRoutes(bird, self.config)

	// Add corresponding neighbour and source rs to result
	results := []api.LookupRoute{}
	for _, src := range routes {
		// Okay. This is actually really hacky.
		// A less bruteforce approach would be highly appreciated
		route := api.LookupRoute{
			Id: src.Id,

			Routeserver: rs,

			NeighbourId: src.NeighbourId,

			Network:   src.Network,
			Interface: src.Interface,
			Gateway:   src.Gateway,
			Metric:    src.Metric,
			Bgp:       src.Bgp,
			Age:       src.Age,
			Type:      src.Type,

			Details: src.Details,
		}
		results = append(results, route)
	}

	// Make result
	response := api.RoutesLookupResponse{
		Api:    apiStatus,
		Routes: results,
	}
	return response, nil
}

func (self *Birdwatcher) AllRoutes() (api.RoutesResponse, error) {
	bird, err := self.client.GetJson("/routes/dump")
	if err != nil {
		return api.RoutesResponse{}, err
	}
	result, err := parseRoutesDump(bird, self.config)
	return result, err
}